Little Bear t10 v2.5 Preamp quality upgrade so far

Discussion in 'Audio Hardware' started by coltlacey1, Jul 25, 2015.

  1. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
    hey guys so I recently received my Little Bear Tube amp. I had been searching for awhile on a new preamp that would give me the sound I was after. I do listen to metal most of the time but on occasion I do like some of the classics such as Bob Dylan, Hendrix, the doors etc. So for these more calm releases I wanted a nice warm sound (to replace the ART djpre2). After much deliberation I ended up buying a little bear. The preamp I received had the Chinese 6N2 tubes with it (and of course the 6Z4 which I am about to get a replacement for). The new board has switches on it that allow you to swap the tubes from 12AX7 to 6N2 which I thought was quite handy. It also has a gain supplement however, it is not adjustable, the gain has high and low setting. I do like having the option to run the gain up, this can be handy with some records but I would like to see it as an adjustable gain.
    The sound has been great since I first hooked it up, I am very pleased with it. It has a nice warm sound, brings out the highs and bass very well. I did end up doing some reading on the tubes though. Supposedly, the Chinese tube are inferior to Russian tubes. I just so happened to be browsing ebay after researching which tubes would be the exact replacement for the 6N2 tubes I was running and came across the Russian 6H2P. these tubes are supposed to be a replacement for the Russian 6AX7. These tubes blew the Chinese 6N2 tubes right out of the water! Definitely seem to have a more defined sound to them and put out more sound at lower volume. Very pleased with this upgrade only ran the tubes for about an hour last night so we will see how they sound after awhile. I read that the Russian tubes are meant to last longer aswell. I think the only thing that bugs me a tad about the preamp is the slight hum sound it puts off but you really only hear it if the gain is on high with volume up high and you are not playing anything. also, you cannot get to the gain switch if the top of the case is on so I run it with the top open. overall, I really enjoy this preamp and it has been fairly simple to find things out about it with more research. the t10 v2.5 is definitely the way to go, the previous versions had some other minor issues. ill include a few photos just for fun.
     
  2. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
  3. vinylkid58

    vinylkid58 Forum Resident

    Location:
    Victoria, B.C.
    Unshielded tubes and close proximity of the power trans. are most likely to blame for any hum. This is a very common issue, especially with the earlier versions.

    jeff
     
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  4. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
    Only thing that would be on would be power supply to the computer. The man who made them specified the hum is just very faint now. I am not too worried about it. i am considering putting it in the cabinet the player sits on.
     
  5. vinylkid58

    vinylkid58 Forum Resident

    Location:
    Victoria, B.C.
    The phono stage has a power transformer. It's the big round shiny doughnut.:)

    jeff
     
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  6. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
    what would normally be covering it? the guy who makes them added an emi filter to the board to quiet the background noise
     
  7. Eduard

    Eduard New Member

    Hi coltlacey1! i have a question:can you please tell me what s the difference in sound between Litlle bear and Art DJ pre 2.I would like to buy an Art but icould wait a litlle to have all the money and go for the Litlle Bear.On what cartridge do you use it?
     
  8. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
    I was using an at120e cart. I am now running an at150mlx. The amp definitely sounds more warm. Seems to hit better highs and is more defined than the art. I am currently breaking in the new Russian tubes as I stated above so I'm thinking the sound might get even better. Just pay attention to the guys sale. He sells them with 12ax7 tubes and 6n2 tubes. Both types are Chinese tubes and I have only ran the 6n2 not the 12ax7.
     
  9. krisjay

    krisjay Psychedelic Wanderer

    Location:
    Maine
    I think you would find the 12AX7 to be a better tube. Spend a little to get a nice vintage AX7 or even a modern EH 12AX7 is decent.
     
  10. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
    I'm actually looking around for some nos 12ax7 tubes now. These ones have served well over the Chinese tubes but I am wanting to upgrade again. Thinking about going the Telefunken direction.
     
  11. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
    Looking at a set of Telefunken Fisher right now. About $170 for three tubes. I doubt it is counter productive to buy tubes near the cost of the amp originally but man it seems strange. Perhaps that's the point, cheaper amp that is very simplistic but is capable of great sound with a nice set of tubes?
     
  12. pbiancardi

    pbiancardi Forum Resident

    Location:
    Dyer, IN
    I just got my Little Bear in, also a 2.5 but looks like a different power supply. I am sure this type of thing is well below the standards of most on this forum but for me this was a huge improvement over what I had. I have a Russound power amp and a cheap Kenwood pre-amp and the difference between running direct to the Kenwood phono in and running from the Little Bear to the aux input is substantial. First LP I played was Black Sabbath Paranoid Rhino reissue, no idea my cheap setup could ever sound this good. Whatever speakers are inside my estate sale cabinet were brought to life by the Little Bear.

    I am dead silent at listening volume but can certainly hear a hum if I turn the knob way up (if I am direct into the Kenwood phono I do not get similar hum with volume knob turned way up). I don't see the hum as an issue, if I turn the volume up to the point that I start to hear the hum and then drop the needle on the LP its WAY louder than I would ever listen to so no issue for me. From what everyone says this newer model is way improved as far as hum goes. For $155.00 and for me this thing is awesome.

    Are you going to shorten the wires at all? I have read that a lot of people do that to lessen the hum and make it look neater?

    I am also curious about the tubes, what would we replace just the three 12AX7's or all of them? Mine came with 12AX7. How do we tell the difference between a "good" tube and a "cheap" tube besides price?

    [​IMG]

    [​IMG]
     
    Last edited: Sep 4, 2015
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  13. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
    I'm in the middle of choices on tubes at the moment. The little bear does a fantastic job for me, I'll have it paired with a yaqin tube amp of some sort next month. I have already purchased tubes for this amp. Bought some No's Russian tubes. They sounded better than the Chinese in my opinion. But, they were still on the lower end of the spectrum for quality. So not I am looking at some Telefunken variants which are a much higher quality tube. The one tube that people have an issue with is the rectifier. That would be your 6z4 tube. I have been searching for a variant tube for some time and have yet to find a proper one. Many people suggest you just stick with this tube because they are not horribly expensive and it does not affect sound much at all according to the manufacturer. As far as the wires go, I honestly hadn't thought about shortening them up but that is a solid idea for sure.
     
  14. pbiancardi

    pbiancardi Forum Resident

    Location:
    Dyer, IN
    Please post your results with different tubes, the stock sound very good so I am going to stick with them but I want to buy a backup set at some point. Like I said this is probably not for most of the guys here but I am very interested in hearing your experiences.

    I am trying to figure out if I would have the same luck with one of their other pre-amps for my Raspberry Pi2.
     
  15. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
    Well, a lot really depends on cost. It's all about how much you want to spend. Like I was saying, those Telefunken tubes and the variants of Telefunken are pretty dang spendy but supposedly produce some of the best sound out there. The Russian 6n2 tubes were pretty cheap for NOS. I purchased the Russian tubes on a whim because I heard they were better over stock which in my opinion they are. A bit more punch from what I noticed. But going from a set of tubes for $15 up to a set for ten times that much.....I would sure as hell hope they perform and sound wayyyyyyy better than these.
     
  16. pbiancardi

    pbiancardi Forum Resident

    Location:
    Dyer, IN
    I shortened my wires, seems to help with hum at high volumes. Does anyone know if I can buy a shield for the tubes? There is one in particular that apparently benefits from shielding, is there an appropriate one to buy rather than try and make one myself?
     
  17. pbiancardi

    pbiancardi Forum Resident

    Location:
    Dyer, IN
    The cheap shield first tube mod makes a huge difference, hum goes completely away unless you really blast it with nothing playing -

    [​IMG]
     
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  18. pbiancardi

    pbiancardi Forum Resident

    Location:
    Dyer, IN
    Anyone know if these are a step up from the stock Chinese?

    12AX7/ECC83 - Mullard, Made in Russia

    Or what should I be looking for, the Chinese stock are sounding good to me but if I can step up performance for another $60 or so for three tubes I'm all in...
     
    coltlacey1 likes this.
  19. vinylkid58

    vinylkid58 Forum Resident

    Location:
    Victoria, B.C.
    You've got two options:

    1. Buy some Russian 6C4P-EV's, which are the same tube as the 6Z4 http://www.ebay.com/itm/4x-6C4P-EV-...New-in-Boix-/201210931062?hash=item2ed91b2776

    2. Change a couple connections at the socket and run the North America equivalent 6X4. Post #377 explains what to do: http://www.audiokarma.org/forums/showthread.php?t=550392&page=26

    jeff
     
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  20. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
  21. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
    Interesting. I wonder if the tube rings would have the same effect as an entire shield?
     
  22. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
    They would be an upgrade. Most the Chinese 12ax7 tubes are pretty cheap. I just swapped out my Russian 6n2 tubes for a set of Raytheon 12ax7a tubes. Much less noise! And the bass seems to be much more apparent, the sound spectrum definitely seems to be quite abit wider. Using dark side of the moon as a tester. I am pleased these tubes are so quiet. I really like that.
     
  23. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
    Wow. And they highs reach up there! Man when those clocks start dinging I could have sworn I was in a room with a bunch of really loud clocks going off....
     
  24. krisjay

    krisjay Psychedelic Wanderer

    Location:
    Maine
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  25. coltlacey1

    coltlacey1 Well-Known Member Thread Starter

    Location:
    Kenai, Alaska
    Yep. And I think the 12ax7s that come in the little bear are no name tubes. I have a bunch of Mullard 12au7 tubes that are pretty nice but I don't think they will do me any good in this amp that's why I installed those older 12ax7a tubes instead
     

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